In a mobile communication system, a base station BTS transmits, receives and processes wireless signals, as shown in FIG. 1(a). A conventional base station comprises a baseband processing sub-system 1, a radio frequency (RF) sub-system 2 and an antenna 3. A BTS may cover a plurality of cells 4 with a plurality of antennae. Each of the base stations (BTSs) is connected to a base station controller (BSC) or a radio network controller (RNC) via respective interfaces. Thus, a radio access network (RAN) is formed, as shown in FIG. 1(b).
FIG. 2 illustrates an architecture of another distributed base station, that is, a centralized base station with remote radio units. As compared with a conventional base station, such a centralized base station with remote radio units has multiple advantages: it is possible to replace a macro-cell based on a conventional base station with a plurality of micro-cells, so that the station would be more adaptable to various radio environments and the wireless performances such as the capacity and coverage of the system could be improved; the centralized architecture makes it possible to perform softer handover than the soft handover in a conventional base station, thereby obtaining additional processing gain; the centralized architecture also makes expensive processing resources for the baseband signals to be a common resource pool shared by a plurality of cells, thereby benefiting from statistically multiplexing and reduces the cost of the system. Details of such a technology are disclosed by PCT Patent Application WO9005432, entitled “Communication System”; U.S. Pat. No. 5,657,374, entitled “Cellular System with Centralized Base Station and Distributed Antenna Units” and U.S. Pat. No. 6,324,391, entitled “Cellular Communication with Centralized Control and Signal Processing”; Chinese Patent Applications CN1464666, entitled “Software Defined Radio Base Station System With Optical Fiber Linked Remote Radio Units and Synchronous Method Thereof” and CN1471331, entitled “Base Station System for Mobile Communication”; and U.S. Patent Application US 20030171118, entitled “Cellular Radio Transmission Apparatus and Cellular Radio Transmission Method”.
As shown in FIG. 2, a centralized base station with remote radio units comprises a central channel processing sub-system 6 that is centrally arranged and remote radio units 7 connected to the sub-system 6 through wideband transmission links 8 or networks. The central channel processing sub-system comprises a channel processing resource pool 9, a signal routing and allocating unit 10 and the like. Here, the channel processing resource pool 9 comprises multiple stacked channel processing units 11, carries out baseband signals processing and the like. The signal routing and allocating unit 10 dynamically allocates the channel processing resources based on the different traffics in the cells to realize effective share of the processing resources among the cells. The signal routing and allocating unit 10 may be either implemented as a separate device outside the central channel processing sub-system 6, or implemented inside the central channel processing sub-system 6, as shown in FIG. 2. A remote radio unit 7 comprises a RF power amplifier for transmission channel (not shown), a low-noise amplifier for receiving channel (not shown), an antenna 12 and other functional units. The links 8 between the central channel processing sub-system 6 and the remote radio units 7 are typically realized with a transmission medium such as optical fiber, copper cable and microwave, where the signal transmission mode may be sampled digital signal or modulated analog signal, and the signal may be baseband signal, intermediate-frequency signal or radio frequency signal. Methods for dynamically allocating channel processing resources based on the different traffics of cells are disclosed in the U.S. Pat. No. 6,353,600, entitled “Dynamic Sectorization in CDMA Employing Centralized Base-station Architecture” and the U.S. Pat. No. 6,594,496, entitled “Adaptive Capacity Management in a Centralized Base Station Architecture.”
In a centralized base station with remote radio units, the wideband transmission links 8 between the central channel processing sub-system 6 and the remote radio units 7 and the antenna 12 are not directly influenced by the radio properties of the radio access networks. Thus, when mobile communication systems of various modes are deployed in one region, the wideband transmission links 8, the station site and BSC or RNC or the like can be shared, thereby significantly shortening the period and reducing the costs for establishing the systems.
However, in the situation that a plurality of mobile communication systems or multiple mobile communication systems of different modes share the wideband transmission links and BSC or RNC, there obviously will appear the problems of conflicts of resource requirements and utilization efficiency of the resources.